1. (v.) To publicly humiliate or embarrass someone. To prove someone wrong in an embarrassing manner. Synonymous with "own" or "pwn."
2. First. Outside. Inside. Last (A rule for binomial multiplication in mathematics.)
3. A thrusting weapon used in fencing.
4. In Australia, a foil, is a $25AUD deal of weed.
5. A $20nzd deal of marijuana wrapped in tin foil,around 10grams. Also refered to as a tinny.

1. HP really foiled Falc by posting his gigantic rambling love letter to her for everyone else to see on the internet.
2. You want a math example? Seriously? Give me a break.
3. He scored a point by putting the point of his foil on his opponent's torso.
4. "Do you sell foil's?"
5. "Yo, do you know where I can score me a foil?"